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Showing 1 to 20 of 28 for “"Shear Driven"”.
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Pressure and velocity fields in a relaxing three-dimensional turbulent boundary layer
… mean velocity data were obtained in a relaxing shear driven three-dimensional incompressible turbulent boundary layer flow produced by a swept rectangular step. The nominally 10 cm (4 in.) thick boundary layer had a freestream velocity of approximately 25 m/sec (80 ft/sec). The two steps …
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The large-eddy simulation of incompressible flows in simple and complex geometries
… later used to investigate a three-dimensional shear-driven cavity flow. The investigation involved Reynolds numbers of 2000, 3200, 5000 and 10000 and focused on the unsteadiness and turbulent characteristics of the flow. At the low Reynolds numbers (Re ~ 5000) where the cavity flow is fully …
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Fatigue crack growth in polycrystalline alumina at high temperatures
… the cyclic fatigue crack was found to advance in shear by the frictional sliding of grains on alternating sets of planes of the maximum shear. Evidence of shear-driven crack growth was supported by topological and morphological analyses of cyclic fatigue crack surface; grain sliding; frictional …
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Near-wall similarity in two- and three-dimensional turbulent boundary layers
Static pressure, mean velocity, indirect wall shear from Preston tubes, direct wall shear using a two-dimensional (single line of action) floating element device, and direct wall shear measurements from an omnidirectional floating element capable of simultaneously determining magnitude and …
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Statistical Stability and Fast Transient Growth in Wall-Bounded Turbulence
Shear-driven turbulence can be generated in wall-bounded flows due to the non-slip boundary. The simple geometry of a wall and thus the shear-driven turbulence are ubiquitous in nature and engineering applications. Hence, prediction and modelling of the turbulence appearance and maintenance in …
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Surface layer processes and nocturnal low-level jet development--an observational study during PECAN
… owing mostly to larger-than-normal generation of shear-driven turbulence. Interestingly, this research also found that the presence of the nocturnal LLJ was highly correlated with values of thermal and dynamic stability that were close to neutral. This result appears to be inconsistent with …
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Shear instabilities in stellar objects: linear stability and non-linear evolution
Shear flows have a significant impact on the dynamics in various astrophysical objects, including accretion discs and stellar interiors. Due to observational limitations the complex dynamics in stellar interiors that result in turbulent motions, mixing processes, and magnetic field generation, are …
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Shear instabilities between accretion disks and nova objects
… on the pre-explosion stage, investigating how shear instabilities and accretion-driven dynamics affect the boundary layer between the accretion disk and the stellar surface. The main goal is to assess how shear-driven mixing modifies the thermodynamic and structural conditions of this region …
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The influence of the land-sea breeze on coastal upwelling systems
… (<∼100 m) surface oscillations are dampened and shear-driven mixing at the thermocline is reduced. Convergence/ divergence of the forced surface oscillations drive evanescent internal waves which elevate local vertical mixing above that from the forced response alone. The internal wave response …
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Instability and Transition to Turbulence in Complex Viscoelastic Flows Overlying Porous Surfaces
… a new mode of viscoelastic instability driven by the coupling between elasticity effects and interfacial permeability. The critical Reynolds number (RRRR) exhibits a strong dependence on WWWW and ββ , with an additional instability branch emerging at higher WWWW. For highly permeable …
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Cleaning viscoplastic soil layers from flat surfaces using impinging water jets
… the soil layer radially outwards in a momentum-driven flow. For very thin soil layers, the liquid film flowed over the soil layer. The transition between these two regimes is related to the relative thickness of the liquid film to the soil layer. A phenomenological model was proposed to describe …
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Un-mixing the Ocean: Double Diffusion and Turbulence in Polar Oceans
… staircases were observed. We find that shear-driven turbulence cannot explain the observed dissipation rates. Utilising the method from the third results chapter, we show that lateral variations in spice can explain the observed turbulent mixing, suggesting it exerts control over the ice …
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An experimental study of a three-dimensional pressure-driven turbulent boundary layer
A three dimensional, pressure driven turbulent boundary layer created by an idealized wing-body junction flow is experimentally studied. The body used is a 3 : 2 elliptical nosed NACA 0020 tailed symmetric profile which has a chord length of 30.5 cm (12 inches), maximum thickness of 7.17 cm (2.824 …
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Some Features of Tip Gap Flow Fields of a Linear Compressor Cascade
… case. The representative flows were pressure driven, three-dimensional turbulent boundary layers in the linear cascade tunnel for the stationary wall case, and the combination of the pressure driven and shear driven flow for the moving wall case. Several experimental techniques are used in the …
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Scale-model investigation of brittle tunnel failure using a true-triaxial device
… as a V-shaped notch formed from progressive shear fracturing and resembled brittle-to-ductile transition. Real-time data on microcracking progression was captured using acoustic emission (AE) sensors during the loading stage, revealing potential precursors on brittle failure onset. …
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